The background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
All publications and patent applications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
Natural killer (NK) cells are cytotoxic lymphocytes that constitute a major component of the innate immune system. Natural killer (NK) cells, generally representing about 10-15% of circulating lymphocytes, bind and kill targeted cells, including virus-infected cells and many malignant cells, non-specifically with regard to antigen and without prior immune sensitization. Herberman et al., Science 214:24 (1981). Killing of targeted cells occurs by inducing cell lysis. NK cells used for autologous NK cell transplants are isolated from the peripheral blood lymphocyte (“PBL”) fraction of blood from the subject, expanded in cell culture in order to obtain sufficient numbers of cells, and then re-infused into the subject. Such autologous NK cells have shown some effectiveness in in vivo treatment. However, such therapy is limited to autologous contexts, and further complicated by the fact that not all NK cells are cytolytic.
NK-92® is a cytolytic cancer cell line which was discovered in the blood of a subject suffering from a non-Hodgkins lymphoma and then immortalized in vitro. NK-92® cells are derived from NK cells, but lack the major inhibitory receptors that are displayed by normal NK cells, while retaining the majority of the activating receptors. NK-92® cells do not, however, attack normal cells nor do they elicit an unacceptable immune rejection response in humans. Characterization of the NK-92® cell line is disclosed in WO 1998/049268 and U.S. Patent Application Publication No. 2002-0068044. NK-92® cells have been evaluated as a therapeutic agent in the treatment of certain cancers.